Judge tells Larry Nassar she signed his 'death warrant' after sentencing him to up to 175 years in jail for sex abuse.

A former US Olympic team doctor has been sentenced to 40 to 175 years in prison for sexually abusing athletes and patients for decades.

The sentencing follows a seven-day hearing in which 156 victims spoke out about the abuse they said they had suffered at the hands of Larry Nassar, the disgraced USA Gymnastics team doctor.

"I just signed your death warrant," Judge Rosemarie Aquilina told Nassar, 54, at the sentence hearing in Lansing, Michigan, on Wednesday.

"It is my honour and privilege to sentence you because you do not deserve to walk outside of a prison ever again."

Accusers include some of the most-decorated gymnasts in Olympic history, including Simone Biles, Aly Raisman, Gabby Douglas and McKayla Maroney.

In a statement read out in court last week, Maroney said: "Dr Nassar was not a doctor. He in fact was and forever shall be a child molester, a monster of a human being, end of story.

"He abused my trust, he abused my body and he left scars on my psyche that may never go away."

Tiffany Thomas Lopez, a softball player, also said in court: "The army you chose in the late '90s to silence me, to dismiss me and my attempt at speaking the truth, will not prevail over the army you created when violating us."

Nassar, who had pleaded guilty to seven counts of first-degree sex assault in Ingham county and three additional charges in Eaton county, both in Michigan, apologised to his victims during the hearing.

He is already serving a 60-year sentence in federal prison for child pornography convictions.